e other fears that had prompted his coming to us in
the first place.

"I've been trying to locate you all over," greeted Craig.

Seabury heaved a sigh and passed his hand, with its familiar motion,
over his forehead. "I thought perhaps you might be able to find out
something from this stuff," he answered, unwrapping a package which he
was carrying. "Some samples of the food I've been getting. If you don't
find anything in this, I've others I want tested."

As I looked at the man's drawn face, I wondered whether in fact there
might be something in his fears. On the surface, the thing did indeed
seem to place Agatha Seabury in a bad light. At the sight of the key in
Sherburne's possession I had grasped at the straw that he might have
conceived some diabolical plan to get rid of Seabury for purposes of his
own. But then, I reasoned, would he have been so free in showing the key
if he had realized that it might cast suspicion on himself? I was forced
to ask myself again whether she might, in her hysterical fear of
exposure by the adroit blackmailer, have really attempted to poison her
husband.

It was a desperate situation. But Kennedy was apparently ready to meet
it, though he seemed to take no great interest in the food samples
Seabury had just brought.

Instead he seemed to rely wholly on the tests he had already begun with
the peculiar tissue I had seen him boiling and the blood serum derived
from Seabury himself.

Without a word he took three tubes from the incubator, in which I had
seen him place them some time before, and, as they stood in a rack,
indicated them lightly with his finger.

"I think I can clear part of this mystery up immediately," he began,
speaking more to himself than to Seabury and myself. "Here I have a
tested dialyzer in which has been placed a half cubic centimeter of pure
clear serum. Here is another dialyzer with the same amount of serum, but
no tissue, such as Mr. Jameson has seen me place in this first one. Here
is still another with the tissue in distilled water, but no blood serum.
I have placed all the dialyzers in tubes of distilled water and all are
covered with a substance known as toluol and corked to keep them from
contamination."

Kennedy held up before us the three tubes and Seabury gazed on them with
a sort of fascination, scarcely believing that in them in some way might
be contained the verdict on the momentous problem that troubled his mind
and might perhaps mean life